Road bikes represent a broad category of cycles engineered with subtleties in design for top performance in particular disciplines. All are meant to be ridden on hard, paved surfaces with speed, efficiency and light weight the priorities. Dropped handlebars permit an aerodynamic riding posture, and multiple gears, changed by means of a derailleur, allow the rider to maintain a consistent cadence.
Road Racing Bicycles
Racing bikes are built as light as possible for maximum amount speed from the rider’s input. The comfort of the rider, load carrying capability and high directional stability are sacrificed by a frame design incorporating steep head- and seat-angles and a very short wheelbase. The frames are very lightweight and often aerodynamically shaped of carbon fiber, steel, titanium or aluminum. Gear ratios are very close, and tires are very narrow with lightweight aerodynamic rims.
Time trial bicycles feature forward jutting aero bars that support the forearms, making the aerodynamic tuck more sustainable. They also can incorporate disk rear wheels, rather than spoked, to lessen wind resistance.
Tri-athlete bicycles, like the time trial bikes, feature aero bars and a frame geometry with 80-degree seat tube angles that provide a more forward-over-the-saddle riding position.
Track bicycles, designed for use in a velodrome, have a single chainring and a single rear sprocket locked into a fixed drivetrain with no freewheel. True track bikes have no brakes, but with many riders discovering the fun of fixed-gear riding on the road, brakes are essential.
Criterium bicycles are stiff and very responsive. They often employ cranks that are shorter in length than other road bikes to allow pedaling deeper into the tight corners found in criterium racing.
Road Touring Bicycles
Touring bikes are designed for load carrying and feature bosses and eyelets to attach racks or panniers. Their longer wheelbases–a result of lengthier chainstays and greater fork rake–and very wide gear ranges (24-30 speeds) give them great versatility and more comfort than racing bikes. Tires wider than those found on road bikes are employed to handle increased weight, and many come equipped with fenders for wet weather riding. Touring bikes are often used as commuting bikes.
Hybrid Bicycles
Hybrids feature a more relaxed geometry with a longer wheelbase and more compliant frame for comfort and added control on street surfaces. The dropped bars of the racing bikes are replaced with a straight bar for a more comfortable 45-degree upright riding position. Tires are generally wide and the gearset somewhat broad. Like the touring bike, comfort bikes are often used for commuting.